About this tool
Find the flow area, wetted perimeter and hydraulic radius of a rectangular channel or a full pipe.
R = A ÷ P. Rectangle: A = b·y, P = b + 2y. Full circular pipe: A = πD²/4, P = πD, so R = D/4.
Formula: R = A/P
Example: Section = Rectangular channel, Width = 3, Water depth = 1.2 → Hydraulic radius = 0.666667.
Use the same length unit for all values.
Quick steps
- Enter your values — every field shows its unit.
- Press Calculate (or Try an example to see how it works).
- Read the results and copy them if you need them elsewhere.
The calculation runs in your browser. Nothing you type is sent to 1CLIK.
FAQ
How does the Hydraulic Radius Calculator work?
R = A ÷ P. Rectangle: A = b·y, P = b + 2y. Full circular pipe: A = πD²/4, P = πD, so R = D/4.
What should I keep in mind?
Use the same length unit for all values.
Is my data sent anywhere?
No. The numbers stay on your device; the page only shows the result.